An unequal trapezoid is given. top base – 20 bottom base – 60 right side – 37 left side – 13
An unequal trapezoid is given. top base – 20 bottom base – 60 right side – 37 left side – 13 Find the area of the unequal trapezoid.
Let us lower two heights from the top of C and B to the base of the trapezoid AD BK = CH, as the heights of the trapezoid.
Let the segment DH = X cm, then AK = (40 – X).
In a right-angled triangle CHD, by the Pythagorean theorem CH ^ 2 = CD ^ 2 – X ^ 2 = 37 ^ 2 – X ^ 2.
In a right-angled triangle ABK, according to the Pythagorean theorem, BK ^ 2 = AB ^ 2 – (40 – X) ^ 2 = 132 – (40 – X) ^ 2.
Since CH = BK, then:
37 ^ 2 – X ^ 2 = 13 ^ 2 – (40 – X) ^ 2.
1369 – X ^ 2 = 169 – (1600 – 80 * X + X ^ 2).
1369 + 1600 – 169 = 80 * H.
2800 = 80 * H.
X = 35 cm.
НD = 35 cm.
Then CH ^ 2 = 37 ^ 2 – 35 ^ 2 = 1369 – 1225 = 144.
CH = 12 cm.
Then the area of the trapezoid is:
S = AD * CH = 40 * 12 = 480 cm2.
S = 480 cm2.
Answer: The area of the trapezoid is 480 cm2.